Dielectric constants of acetonitrile, gamma-butyrolactone, propylene carbonate, and 1,2-dimethoxyethane as a function of pressure and temperature

The dielectric constants epsilon of 1,2-dimethoxyethane, acetonitrile, gamma-butyrolactone, and propylene carbonate were determined from capacitance measurements extrapolated to infinite frequency; In epsilon are reported as a function of pressure up to 80 MPa at 15, 25, 35, 45 degrees C and as a function of temperature in the range 10 to 500C at 0.10133 MPa. The variation of In epsilon with temperature or pressure can be expressed by a second order polynomial expression. The isothermal compressibilities beta of the solvents were determined at 25 degrees C from sound velocities, densities, and heat capacities. A simple correlation can be established between partial derivative ln epsilon/partial derivative P and beta for most aprotic solvent.